class_docstr: Simple scheduler that just runs trials in submission order.
code: def debug_string(self) -> str:
      return "Using FIFO scheduling algorithm."
  
imports: from typing import Dict, Optional, TYPE_CHECKING
  from ray.air._internal.usage import tag_scheduler
  from ray.tune.result import DEFAULT_METRIC
  from ray.tune.experiment import Trial
  from ray.util.annotations import DeveloperAPI, PublicAPI
label_desc: Use image node_id 8 for calling the FIFOScheduler obj's underlying member method code with example usage: obj.debug_string() and returns: str